vbox
vbox is the real implementation of abstract type box.

box instances can be created from hbox, and vbox respectively.
box has child widgets stored in a GList with data pointer
to the structure 'GtkBoxChild'.

You see  add elements to a vbox using the function of box API.

Adding from the start for a Vbox implies  that the elements
get added from top-bottom. conversely for a adding from end, implies
a bottom-top addition order of widget.

Creating a new vbox is a simple matter of using the constructor
GtkWidget* gtk_vbox_new	     (gboolean homogeneous,
			      gint spacing);
if TRUE, homogenous sets all child widgets to same size,
and spacing is the requested space between child widgets.

see also: box, container